1. Field of the Invention
This invention relates to improvements in apparatus for the construction of three dimensional models and more particularly, but not by way of limitation, for the construction of relief maps directly from contour maps.
2. Description of the Prior Art
Relief maps and three dimensional models are very useful in many industries, as for example in construction operations involving highway construction, large buildings, and the like, wherein large volumes of earth must be replaced during the construction operation. For example, during the construction of a highway, scale model relief maps, and the like, are frequently utilized to provide an accurate indication of the quantity of earth displacement that will be necessary during the usual cut and fill operations. The amount of earth displacement is a critical factor in establishing bids for construction jobs of this nature, and therefore must be given very careful consideration. In oil exploration, an accurate visual view of sub-surface strata formations is needed to determine potential productive well locations. The use of different materials for different formations lends itself to model analysis in the laboratory, thereby increasing the possibility of a successful drilling operation.
At the present time, the usual scale models of terrain features or sub-surface strata formations are established by providing layers of material, such as paper board, that equal the thickness of the differential levels established by the contour lines of the topographical or sub-surface strata map relating to the territory, and overlaying the layers of material that correspond to its relative size in relation to the size of the area encompassed by a given contour line of the topographical map. This is a very time consuming and expensive procedure which adversely affects the commercial feasibility of the construction and oil exploration operation.
Devices have been developed for facilitating the construction of relief or contour maps, such as the Cadman U.S. Pat. No. 1,683,952; Johnson U.S. Pat. No. 2,988,825; Walker U.S. Pat. No. 2,999,634; Lucy Pat No. 2,410,888; French Pat. No. 1,011,841 and Russian Pat. No. 252,256. The Johnson patent discloses a vacuum framing apparatus for forming a temporary relief map, and the contour form includes a plurality of stacked layers of flat material, each cut to the required contour. These layers provide a form which supports a flexible membrane whereby the desired relief map is produced when the membrane is pulled down over the form by vacuum drawn through the bottom of the container. An electrode arrangement may be used to determine pressures in the formations to which this arrangement conforms, thus defining a more or less automatic method of forming the layers.
The Walker patent discloses a contour device in which cables connected to the underside of a flexible surface of the contour device are adjusted proportional to various measurements taken to determine contour. The cables are connected to the crossing grid points of the grid on the flexible material and are arranged to be individually extended or shortened to flex the surface of the covering material. This arrangement enables adjusting of the surface or covering material to simulate the surface of the area of interest. To make cut and fill measurements, air under pressure is introduced into the chamber beneath the membrane, and the volume of displaced air is taken as a measure of the volume of material to be moved, taking into consideration appropriate multipliers to correct for the difference in size between the model and the actual area. The Cadman reference discloses a pantograph in which rods having indicator bushings are used for the purpose of mapping or planning a formation based on available data, and the French patent shows a tracer type device which apparently facilitates the cutting of a relief model based on tracing or following the contour of the lines of a contour map. The cutting action appears to be accomplished by the outward tension on the cable as the rod is moved along the desired contour.
The Lucy patent discloses an apparatus for molding three dimensional shapes from drawings wherein a plurality of rows of pins have their adjacent ends adjusted into positions coordinated with a contour line of a drawing thereby collectively defining the contour of the line and a matrix supported by the ends of the pins conforming to the defined composite shape. The Russian patent is a cavity gauge which checks the depth and general profile or shape without using wax, or the like.